The present invention generally relates to an electromagnetic apparatus consisting of a pair of contactors, and, more particularly, to an interlocking mechanism provided within the electromagnetic apparatus for controlling the alternative operations of the pair of contactors.
Generally, an electromagnetic apparatus is adapted to open and/or close a fixed point of contact by a movable insulation stand having a moving point of contact through a polar contact reciprocating in accordance with the excitation or de-magnetization of an electromagnetic device, said electromagnetic device, polar contact, movable insulation stand and contact mechanism including the fixed point and moving point of contact being accommodated in series within a casing. Also, there has been proposed an electromagnetic apparatus consisting of a pair of contactors each having the same arrangement as that of the above electromagnetic apparatus, with the casing of one contactor being combined in parallel connection with the casing of the other contactor in one unit. In the electromagnetic apparatus combining two contactors within one casing, an interlocking mechanism is provided within the casing to control the contactors in such a manner that, when either one of the contactors is at the state of operating, the other of the contactors is interlocked not to operate by any means. Conventionally, such an interlocking mechanism is provided with a pair of interlock levers each pivotally connected with the corresponding movable insulation stand by means of a pin or shaft and is so arranged to make an interference with the other that the contactors are adapted to operate one by one so as to prohibit the simultaneous operation with each other. However, the interlocking mechanism of the above type has disadvantages such that the connecting means of pin or shaft is rendered to design to have a small dimension due to existing a space problem of the casing, and to assemble with a small clearance provided between the pin or shaft and a hole provided on the lever to be fitted with the pin or shaft in order to maintain the precise operation of the interlocking mechanism, thereby to cause not to provide enough strength for the interlocking mechanism, and not to facilitate the assembling of the interlocking mechanism.